1. Field of the Invention
The present invention relates generally to a device and method for protecting content, and more particularly, to a storage device, a host device and a corresponding method for securely storing and playing content.
2. Description of the Related Art
Content protection technology aims to securely deliver a variety of content from Content Providers (CPs) to users, and to prevent users, who have received content, from illegally distributing the content. Content protection technology may protect information throughout an entire process that includes creation, distribution, usage and disposal of digital content. Content protection technology may also protect the rights of users, both online and offline.
Content protection technology may include, for example, Digital Rights Management (DRM) technology, Content Protection for Recordable Media (CPRM), and Advanced Access Content System (AACS) specification. A content protection approach also exists that encrypts and provides content itself, provides control information for controlling usage of encrypted content, and provides an encryption/decryption key for decrypting the encrypted content.
According to this content protection approach, an entity consuming content (hereinafter referred to as a ‘host’), such as a content playback device, receives control information corresponding to encrypted content and an encryption/decryption key. The host decrypts the encrypted content based on the control information and the encryption/decryption key. The host may receive the encrypted content, the control information and the encryption/decryption key from a storage device having a Secure Area (SA), access to which is available to the host, after the host has passed authentication. In contrast, the host may receive the encrypted content separate from the control information and the encryption/decryption key, which are received from a storage device having an SA. The storage device may be a Non-Volatile Memory (NVM) device having an SA, such as, for example, a Secure Digital (SD) card and a Universal Serial Bus (USB) memory.
As described above, conventional content protection technology provides content that is encrypted using a unique media identifier (ID) and its associated encryption technology (e.g., Public Key Infrastructure (PM) authentication). Conventional content protection technology maps the content or an encryption key used to encrypt the content, to the unique media ID, thereby preventing access to a storage area of a storage device, i.e., preventing an improper operation (reading, writing, etc.) for illegal replication of data.
However, conventional technology does not provide clear information for mapping encrypted content, control information and a decryption key, for consumption of the encrypted content.
Specifically, FIG. 1 shows encrypted content, control information for controlling usage of encrypted content, and decryption keys. Control information 121-123, which control usage of encrypted content, and decryption keys 111-11N may be stored in a storage device 100. In particular, the decryption keys 111-11N may be stored in separated areas SA1-SAn of an SA 110, respectively.
In order to consume or play each of the encrypted contents, such as Encrypted Content A 201, Encrypted Content B 202, and Encrypted Content C 203, a host, such as a content playback device, acquires associated control information and an encryption/decryption key from the storage device 100.
For example, to play the Encrypted Content A 201, the host acquires, from the storage device 100, ‘Usage Information for A’ for usage of Content A and ‘Information bound to A’ associated with Content A, which are included in control information ‘002.ctrl’ for the Encrypted Content A 201. The host also acquires, from the SA area 110, an encryption/decryption key, ‘Title key’, corresponding to the ‘Usage Information for A’ and the ‘Information bound to A’, in order to consume or play the Encrypted Content A 201.
However, conventional technology does not provide information indicating the area in which a title key corresponding to the content is stored. Accordingly, when a title key is stored in the SA area 110, the host may not acquire the correct title key.